A massive section of ironwork collapsed at Toronto's Downsview Park Saturday afternoon prior to Radiohead's planned show there, leaving one dead and three injured.

According to Toronto Police, the deceased man was in his thirties. Given that the show was not yet open to the audience, he was likely a member of Radiohead's tour crew. The man's name is not yet being released until such time as police are able to notify his family. Two of the injured were treated and released with minor injuries. The third, 45 years old, sustained a serious, but not life-threatening injury to his head.

It's not clear if the victims were working on the elevated metalwork or on the stage level when the collapse occurred.

So far Radiohead's only comment has been via their Twitter, which posted what appears to be a hastily written message just after 5 pm ET. "Due to unforeseen circumstances tonight's at downsview park tonight has been cancelled. Fans are advised not to make their way to the venue."

The CBC spoke to several concessionaires who were on scene at the time of the accident. Alexandra Mihan reported a sound like fireworks, then hearing screaming and gasping. "We turned around, and the entire top of the stage has just collapsed. All of the metalwork and all of the screens had just kind of folded over on top of each other." Photos and videos making their way across the Internet on Saturday painted a similarly grim picture.

Beer vendor Jeff Cole added, "It's very, very fortunate that the gates weren't open, because it would have been pandemonium."